Hennepin County Judge Peter Cahill reinstated the charge after the former officer, Derek Chauvin, failed to get appellate courts to block it.
Cahill had earlier rejected the charge as not warranted by the circumstances of Floyd’s death, but an appellate court ruling in an unrelated case established new grounds.
Legal experts say the additional charge helps prosecutors by giving jurors another option to find Chauvin guilty of murder.
The dispute over the third-degree murder charge revolved around wording in the law that references an act “eminently dangerous to others.” Cahill's initial decision to dismiss the charge noted that Chauvin’s conduct might be construed as not dangerous to anyone but Floyd.
Floyd’s death sparked sometimes violent protests in Minneapolis and beyond, leading to a nationwide reckoning on race.